The present invention relates generally to eggs and, more particularly, to methods and apparatus for processing eggs in ovo.
Injections of various substances into avian eggs have been employed to decrease post-hatch mortality rates, increase the potential growth rates or eventual size of the resulting chicken, and even to influence the gender determination of the embryo. Similarly, injections of antigens into live eggs have been employed to incubate various substances used in vaccines which have human or animal medicinal or diagnostic applications. Examples of substances that have been used for, or proposed for, in ovo injection include vaccines, antibiotics and vitamins. In addition, removal of material from avian eggs has been employed for various purposes, such as testing and vaccine harvesting. Examples of in ovo treatment substances and methods of in ovo injection are described in U.S. Pat. No. 4,458,630 to Sharma et al., U.S. Pat. No. 5,028,421 to Fredericksen et al., and U.S. Pat. Nos. 6,032,612 and 6,286,455 to Williams, the contents of which are incorporated by reference herein in their entireties.
An egg injection device conventionally is designed to operate in conjunction with commercial egg carrier devices or flats. The injection device may comprise a plurality of injection needles which operate simultaneously or sequentially to inject a plurality of eggs, or a single injection needle used to inject a plurality of eggs. The injection device may comprise an xe2x80x9cinjection headxe2x80x9d which comprises the injection needle or needles, and wherein each injection needle is in fluid communication with a source containing a treatment substance to be injected. A single fluid source may supply all of the injection needles in an injection device, or multiple fluid sources may be utilized.
An exemplary in ovo injection apparatus 10 is illustrated in FIG. 1. The illustrated apparatus 10 includes a flat 15 for carrying eggs 20, a stationary base 16, and a plurality of injection delivery devices, or heads, 25 with fluid delivery means such as lumens or needle(s) positioned therein in accordance with known techniques. The flat 15 holds a plurality of eggs 20 in a substantially upright position. The flat 15 is configured to provide external access to predetermined areas of the eggs 20. Each egg 20 is held by the flat 15 so that a respective end thereof is in proper alignment relative to a corresponding one of the injection heads 25 as the injection head 25 advances towards the base 16 of the apparatus.
In ovo injections of substances (as well as in ovo extractions of material) typically occur by piercing an egg shell to form an opening (e.g., via a punch), extending an injection needle through the hole and into the interior of the egg (and in some cases into the avian embryo contained therein), and injecting treatment substance(s) through the needle and/or removing material therefrom. For example, each injection head 25 of the apparatus of FIG. 1 includes a punch 26 and an injection needle 27 with the punch surrounding the needle 27 in coaxial relationship therewith as illustrated in FIGS. 2A-2B. The punch 26 is configured to pierce the egg shell and the needle 27 is configured to deliver a substance into the egg (FIG. 2B).
Egg flats utilized in conjunction with in ovo injection devices contain an array of pockets that are configured to support a respective plurality of eggs in a generally upright orientation. An exemplary egg flat 30 is illustrated in FIGS. 3A-3B. The illustrated egg flat 30 includes a plurality of rows of pockets 32. Each pocket 32 is configured to receive one end 20a of a respective egg 20 so as to support the respective egg 14 in a substantially vertical position. Each pocket 32 of the illustrated egg flat 30 contains a plurality of tabs 34 (FIG. 3B) that are configured to support a respective egg as illustrated in FIG. 4.
Although effective in supporting eggs during transport, these support tabs 34 can damage eggs during in ovo processing. The force applied to an egg by an in ovo processing punch can push the egg downwardly against the support tabs 34 with sufficient force to cause the egg to crack. In addition to reducing hatch rates, cracked eggs can lead to contamination of other eggs within an egg flat, as well as contamination of processing equipment.
In addition, support tabs in conventional egg flats are somewhat flexible and can deflect when an egg supported thereby is punched. In addition, conventional egg flats are typically somewhat flexible. As such, during punching of a plurality of eggs, the egg flat structure can warp and/or twist. This warping and/or twisting of the egg flat can add to the deflection of the support tabs such that when the force of punching is removed the egg flat and tabs can grip an egg, thereby making removal from the egg flat difficult. Accordingly, it would be desirable to be able to punch through the shell of an egg supported within an egg flat without causing the egg to crack and without causing the egg to become stuck within the egg flat.
In view of the above discussion, methods and apparatus for forming an opening in a shell of an avian egg such that the potential for cracking is greatly reduced are provided and comprise moving a punch through an egg shell at speeds equal to or greater than thirty (30) inches per second. In order to protect the air cell of an egg, to avoid contamination, and, in the case of allantois sampling, to avoid penetrating an adjacent membrane, punch travel is stopped immediately upon entering an egg. According to embodiments of the present invention, punch travel is stopped via energy-absorbing material positioned between an egg and the housing or support structure of the punch. According to other embodiments of the present invention, punch travel can be stopped by the punching tool body which can be clamped during punching. Punches may be driven via various devices including gravity-assisted devices, spring-assisted devices, solenoid-assisted devices, voice coil-assisted devices, and fluid-assisted (e.g., compressed air, compressed nitrogen, liquid, etc.) devices. Punches according to embodiments of the present invention may also be configured to deliver treatment substances into eggs.
According to embodiments of the present invention, the shell of an egg may be pierced without causing cracking by hurling one or more small projectiles at the egg shell at speeds in excess of 30 inches per second. According to embodiments of the present invention, a non-toxic, biodegradable material (e.g., ice) is used as a projectile. According to embodiments of the present invention, a projectile may contain a predetermined dosage of a treatment substance.
According to embodiments of the present invention, the shell of an egg may be pierced without causing cracking by moving a punch through an egg shell at speeds equal to or greater than thirty (30) inches per second and then hurling one or more small projectiles (e.g., ice) within an egg to penetrate the membrane at the floor of the air cell and/or to deliver a predetermined dosage of a treatment substance.
According to embodiments of the present invention, a punch may be mounted on a piezoelectric actuator or electromagnetic actuator configured to vibrate at frequencies in a range of between about 1,000 Hz and about 100,000 Hz. These frequencies effectively cause a punch to move at speeds in excess of 30 inches per second.
Downward motion of an egg due to egg flat and support tab deflection during punching increases the energy required for punching the egg. For example, eggs typically move downward about xe2x85x9 inch to {fraction (3/16)} inch during punching due to egg flat and support tab flexure caused by conventional punching forces averaging about six pounds per egg. Total energy expended by a punch tool, U, equals force integrated over distance (or in the case of a linear relationship between egg deflection and force U=0.5*F*d where F is peak punch force and d is maximum flat deflection). Total punch work is therefore about 0.03 to 0.04 foot-pounds via conventional punching techniques. Measurements of energy required to punch a rigidly supported egg are about {fraction (1/100)} foot-pound. Thus conventional punching with the attendant flat deflection can increase the energy required to punch an egg by a factor of three to four.
Embodiments of the present invention can be advantageous over conventional egg shell punching apparatus and methods because less energy may be required to form openings within egg shells. Punching speeds in excess of 30 inches per second do not appear to allow energy to be expended in deflecting the support tabs within egg flat pockets, the egg flat, or the structure supporting either the egg flat or the punch tool(s). As a result, smaller punch actuators that are lighter in weight and less expensive/complex than conventional actuators may be utilized, which may result in cost savings.